Grandma White is a Taoist fairy, also known as the "Kowloon Fairy". According to legend, she practiced in Jiulong Mountain, West Shui Ye Town, Anyang City, and her prototype was White Snake. Guanyin Bodhisattva is a fairy in Buddhism. They are different.
In some places, Grandma White is regarded as a fairy in folklore. She has the ability to live long and benefit for life. In other places, Grandma White is regarded as one of the incarnations of Guanyin Bodhisattva. Because Guanyin Bodhisattva often wears white clothes in legend, she is called "Grandma White".
Generally speaking, Grandma White and Guanyin Bodhisattva are two different immortals. Although they may be confused or regarded as the same immortal in some places, they are not the same.